diigo-cache: README sells and gets to TADA; CONTRIBUTING updated

New README: two sentences, the dev run through connect, fill, and a
filtered public page, then features. CONTRIBUTING gains the 1d
filters and its own run and deploy sections instead of pointing at
the checklist; links to the old README now point at CONTRIBUTING.

Generated-by: Claude Opus 5.5

capsite-checklist.md

@@ -23,7 +23,7 @@ narrative.
         goal 5.
 
   - [x] **1c. diigo-dump evolves into a bookmark cache**
-        ([diigo-cache/README.md](diigo-cache/README.md); design in the
+        ([diigo-cache/CONTRIBUTING.md](diigo-cache/CONTRIBUTING.md); design in the
         JSDoc of `src/cache.ts`, `src/index.ts`, `src/pm-save.ts`):
         - [x] 1c-i. Two independent page caches, private and public
               (`PagedCache`, `DiigoCache`, `PublicCache`).
@@ -113,7 +113,7 @@ narrative.
   - [ ] **5. Deployed end-to-end** (order matters):
         - [ ] 5-i. webapp: `cd webapp && npx wrangler deploy`
         - [ ] 5-ii. diigo-cache: rate-limit `/api` (and `/public/*`) first
-              (diigo-cache README, "Deployment concern"); deploy; create
+              (diigo-cache CONTRIBUTING, "Deployment concern"); deploy; create
               against prod (ids → password manager; no worker secret);
               run the fill job.
         - [ ] 5-iii. madmode: deploy with the service binding; the
@@ -235,5 +235,5 @@ to every goal in this tree.
   Oct 6 2026)
 - [webapp/README.md](webapp/README.md) — HTTP + RPC surfaces of the
   factory worker; open TODO on the mint-form placement
-- [diigo-cache/README.md](diigo-cache/README.md) — the cache worker:
+- [diigo-cache/CONTRIBUTING.md](diigo-cache/CONTRIBUTING.md) — the cache worker:
   create flow, the two DOs, run/deploy details